Boosting machine availability through condition monitoring

Predictive maintenance based on constant condition monitoring helps avoid unplanned downtime and reduces the cost of stocking spare parts. Using condition measurements as input for open and closed control loops can significantly increase the service life of a machine and contribute to substantially reduced unit costs.

Condition monitoring is already an integral part of every B&R system and of every machine automated with B&R technology.

B&R Automation offers a wide range of products from oscilloscope modules and sensor-equipped servo drives to the monitoring chip inside every Automation PC and vibration analysis modules with embedded intelligence to help monitor machines without requiring any external units.

The development efforts of mechanical engineers are paying off as the power density and functional density of production machines continue to increase, requiring fewer machines to produce the same quantity and complexity of products, which lowers production costs and makes machine manufacturing more competitive.

However, increased machine efficiency also makes producers more dependent on individual machines with the ability to produce more units per hour translating into greater expense per hour of downtime.

Traditional maintenance strategies have their own shortcomings and involve considerable financial risk. Even preventive maintenance at fixed intervals, though planned cannot be considered as a cure-all solution as it offers no reliable protection against unplanned downtime.

Responsible managers work towards a goal of minimising downtime as much as possible and crafting a strategic plan for maintenance by not only considering the purchasing price when evaluating new machines, but also the overall costs over their entire useful life. The only way to significantly impact the total cost of ownership is to maximise machine uptime while simultaneously minimising maintenance costs.

Condition-dependent predictive maintenance

Condition-dependent predictive maintenance is an ideal way to optimise the ratio of machine availability to maintenance costs. This involves scheduling maintenance when changes in monitored parameters indicate impending failure.

A key advantage of condition monitoring is that components can continue to provide value until much closer to the actual end of their useful life, which is typically much later than the conservatively estimated maintenance interval. This approach does not compromise planned maintenance as it can be performed during regularly scheduled breaks in production.

The risk of maintaining a stock of replacement parts is also minimised since only the affected components need to be replaced. Additionally, failures resulting from neglected maintenance can also be reliably avoided.

Condition-dependent predictive maintenance involves monitoring condition parameters throughout the machine, and evaluating the data correctly to determine which parts require maintenance. Bernhard Eder, business manager at B&R explains that it can be based on simple signals and measurement values such as temperature or pressure that are collected using X20 or X67 I/O modules. B&R also offers specialised modules such as valve control modules with integrated switching time detection or oscilloscope functions.

B&R automation systems incorporate several options for monitoring condition signals including ACOPOS servo drives with built-in motor monitoring as well as B&R Automation PCs, which are equipped with an integrated circuit for self-diagnostics in addition to a new module in the X20 series for vibration analysis.

According to Werner Paulin, B&R's international sales manager for China, the key to scheduling maintenance intervals for replacing components at the right time, but not too early, is correct interpretation of the recorded signals, leading to the accurate prediction of developing problems.

Condition monitoring has been slow to take hold in traditional machine manufacturing due to the complexity involved, and has been limited to systems whose failure would result in immense costs.

With B&R’s condition monitoring solutions however, machine manufacturers are able to offer condition monitoring not as a premium option, but as a fully integrated standard feature.

B&R's analogue input module X20AI2636, for example comes standard with essential functions such as a comparator with hysteresis. The X20CM4810 condition monitoring module from B&R converts signals read from the acceleration sensors into more than 70 specific values, allowing even complex oscillation patterns to be monitored on a single channel.

Developers can easily configure which factors should be monitored in B&R Automation Studio without requiring knowledge of complex mathematical functions, thereby solving a lot of problems with regard to software and interfaces.

Machine operators can also benefit from the integration of condition monitoring with a company's internal logistics systems. When the machine identifies the need for maintenance, for example, it can automatically trigger a reminder to the maintenance or purchasing department for the required parts, preventing orders from being overlooked or placed incorrectly and ensuring that the right part is on hand when it is needed without having to maintain a large stock on site.

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